Users can use a variety of devices, such as PCs, tablets, mobile phones, and other computing devices (generally, computing entities) to consume and/or interact with online content. Further, users can use separate browsers or applications on the same device or different devices to consume and/or interact with online content. Each device, browser, and/or application can have its own technical identifier. For example, IOS devices can utilize an Identifier for Advertisers (“IDFA”) or ANDROID devices can utilize an Advertising ID. Browsers can utilize other identifiers, many of which can be stored in cookies. Ad systems can collect behavioral data based on a computing entity's interactions with websites and other online content. Because each device, browser, and/or application can have its own technical identifier, determining whether a particular computing entity is associated with a known user can be difficult. Further, being unable to efficiently determine whether the computing entity is associated with a known user can impede leveraging any behavioral data already possessed for that user (e.g., based on the activity of other computing entities).